We hypothesize that certain risk factors including, but not limited to, genotype, hemangioma size, hemangioma location, cerebral anomalies, cerebellar anomalies, and cerebrovascular anomalies predispose patients to progressive vasculopathy. We will determine risk factors and identify biomarkers for progressive cerebrovascular disease. Based on this information we will establish guidelines for serial and diagnostic cerebrovascular imaging and develop a method of risk-stratification that will allow for early clinical prediction and intervention of long-term neurodevelopmental prognosis. Specific Aims